I think I've read about this someplace on here before, but couldn't find it.

I have a flight this summer that has had a couple minor schedule changes - a few minutes here & there. As a result, the seatmap for those segments are no longer visible - and I'm no longer able to check/change my seat assignments online - when I pull it up in "My Itineraries".

Is there a simple way to get these back so I can make changes without going through the automated hell of SMS?